People who drink herbal tea, even as little as once a week, may have a reduced risk of distal colon cancer, according to local collaborative research.

The study explored the effect of hot coffee, iced coffee, herbal tea and black tea on the risk of proximal colon, distal colon and rectal cancers.

Curtin University Professor Lin Fritschi says the relationship between herbal tea and decreased risk of bowel cancer was their most statistically significant finding and may warrant further investigation.

"Whether or not the relationship between the herbal tea and decreased risk of cancer is a "real" effect needs to be confirmed in other studies," Prof Fritschi says.

"One of the reasons people who drink herbal tea may have a reduced risk is that overall, they have a healthier diet than those who don't.

"The tea might just be a marker for that, not the actual protective factor.